It's a tool use to make steady lines for anime artist. It's very helpful for mouse user and beginners to create nice fine lines, I guess.
There is come explaining on this RMD tutorial, scroll down and you'll see.
Edit: Oops sorry, wrong link. Here's the right one.
http://www.ratemydrawings.com/tutorials … vised.html
Last edited by Jyuliey (19 Aug, 2014 2:44 pm)